The present invention relates to complimentary metal oxide semiconductor (CMOS) structures, and more specifically, to a semiconductor structure having an improved silicon-on-insulator (SOI) body contact capable of preventing a floating body effect.
In a typical SOI device, the body of the device is electrically isolated between source and drain regions of the device. Floating body effects occur based on the accumulation of charge carriers in the body of the device. Floating body effects also cause fluctuations in threshold voltage of the device. This problem is apparent for devices such as those used in dynamic random access memory (DRAM) where it is critical that the threshold voltage remain fixed such that the device remains in an off position to prevent charge leakage from the storage capacitor. Body contacts are intended to prevent floating body effects in the device. These contacts are needed when precise device behavior is required. Thus, the body contact is used to electrically connect the body of the device to a fixed potential to prevent floating body effects.
Conventional body contacts may require additional area within the device or problems may occur when connecting the body to the fixed potential such as high impedance or grounding issues.